Switch for refrigerators



May 6, 1952 e. s. M CLOY 2,595,967

SWITCH FOR REFRIGERATORS Filed Feb. 11, 1950 2 SHEETS--SHEET 1 WITNES'ES: INVENTOR M Graham s. M'cCloy g %Q5% ATTORNEY y 6, 1952 G. s. MCLOY 2,595,967

SWITCH FOR REFRIGERATORS Filed Feb. 11, 1950 2 SHEETSSHEET 2 INVENTORGruhum 5v McGloy ATTORNEY Patented May 6, 1952 SWITCH FOR REFRIGERATORSGraham S. McCloy, Springfield, Mass., assignor to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of PennsylvaniaApplication February 11, 1950, Serial No. 143,788

3 Claims.

This invention relates to refrigerating apparatus and more especially toa defrosting control for such apparatus.

Automatic defrosting controls actuated by a predetermined number of dooropenings frequently employ a ratchet wheel which is advanced by theopening and closing of the refrigerator door. When this wheel completesone revolution, it engages and moves a control member into position toefiect defrosting. This member must be released automatically after ithas fulfilled this function so that the defrosting operation may beterminated by another device even though no further door openings andclosings have taken place.

It is an object of the invention to provide a novel means for releasingthe defrost control member when the defrosting cycle has been initiated.

It is another object of the invention to provide a novel defrostingcontrol in which the defrosting period may be terminated without furthermovements of the actuating member after the defrosting cycle has beeninitiated.

It is a still further object of the invention to provide novel means foractuating a ratched wheel.

These and other objects are effected by my invention as will be apparentfrom the following description and claims takenin connection with theaccompanying drawings, forming a part of this application, in which:

Fig. 1 is a view in perspective of a refrigerator cabinet embodying thedefrost control of this invention;

Fig. 2 is a view of the defrost control of this invention with the coverremoved;

Fig. 3 is a sectional view of the defrost control of this inventiontaken on the line III-III of Fig. 2;

Fig. 4 is a slightly enlarged view in perspective of the movable dog ofthe ratched device of the defrosting control;

Fig. 5 is a view in perspective of the snapacting switch plate elementof the defrost control; and

Fig. 6 is a schematic drawing of the defrost control of this inventionand its application to refrigerating apparatus.

Referring to the drawings and more especially to Fig. 1, the referencenumeral l0 designates a refrigerator cabinet embodying the defrostingcontrol of this invention. A plunger I2 is projected from the cabinet IDby a spring 50 when the door 14 of the cabinet I0 is opened and isdepressed by the door l4 when the door 14 is 2 closed. The plunger 12 isjoined by means not shown to a sliding element [6, best shown in Figs. 2and 3. The sliding element It comprises a rectangular portion l'! whichprojects into a housing 18 and slides in a rectangular groove 20therein. The closing of the door [4 moves the sliding element l6upwardly as viewed in Figs. 2 and 3 and the spring 58 moves the elementdownwardly when the door [4 is opened.

A toothed ratchet wheel 22 is journaled on a portion 24 (best shown inFig. 3) of the housing I8. A U-shaped spring element 26, cut from fiatsheet material, is secured to the housing l8 b means of a screw 28. Oneleg 30 of the spring element 26 overlies the ratchet wheel 22 to hold iton its journal. The other leg 32 overlies the journal of the ratchetwheel 22 and is preferably spaced slightly from a sliding pin 34 whichprojects through the journal.

A spring 35, formed of sheet material and best shown in Figs. 2 and 4,comprises a generally L- shaped actuating element 36. One leg 38 of thiselement 36 is fixedly secured at its lower end to the housing IS. Theupper end of the leg 38 includes a portion 39 which is bowed to theright as viewed in Fig. 2. The other leg 40 of the L- shaped actuatingelement 36 extends horizontally to the left. The free end of the leg 40is notched at 42 and overrides. the ratchet wheel 22 to engage a toothon the periphery thereof.

The sliding element It has a depression 44 including an inclined face46. The bowed out portion 39 of the actuating element 36 is biased bythe leg 38 into the depression 44, and as the element 1 6 slidesupwardly, as seen in Figs. 2 and 3, in response to the closing of therefrigerator door I, the inclined -face 46 engages the bowed out portion39 of the actuating element 35 and moves it together with the leg 4!] tothe left as viewed in Fig. 2. This leftward movement of the leg 40advances the ratchet wheel 22 in a counter clockwise direction. Thespring 35 also comprises a stationary dog 48, which also engages a toothof the ratchet wheel 22 and prevents clockwise rotation thereof.

When the refrigerator door [4 is again opened, the sliding element It isurged downwardly as viewed in Fig. 2 by the spring 50 so that the bowedout portion 39 of the actuating element 36 together with the leg 40moves to the right and into the depression 44. The leg 40 is resilientso that the free end of the leg 40 rides over one or more teeth of theratchet wheel 22 to engage an adjacent tooth.

It will be observed that the bowed portion 39 of the actuating element36 forms a follower for the cam surface 46 of the sliding element I6. Itis biased against the cam surface 46 by the leg 38 which is relativelystraight to afford stiffness against vertical movement of the bowedportion 39 as viewed in Fig. 2. The leg 4% lies substantiallytangentially to the ratchet wheel 22 to afford stiffness to insuretransmission of the movement of the bowed portion 39 to the teeth of theratchet wheel 22. The tangential position of the leg 40 also affordsresilience to the movement of the free end of the leg 40 radially of thewheel 22 which movement allows the free end of the leg 40 to ride overthe teeth of the ratchet wheel 22.

The ratchet wheel 22 carries a wedge shaped cam 52 which is graduallyforced under the leg 32 of the spring element 26 as the wheel 22 remotorfordriving the compressor.

as viewed in Fig. 3 by a flexible metal bellows 80 which forms one wallof the vessel 82 which vessel communicates with a tube 84. The movementof the pin I8 to the right is opposed by a spring 86, one end of whichengages the head 88 of the pin I8 and the other end of which engages aplate 90, the position of which is adjusted by means of a screw 92.

The connection of the defrost control of this invention to arefrigerating unit is shown diagrammatically in Fig. 6 in which thevarious elements of the defrost control are designated with thepreviously used reference numerals. The refrigerating unit comprises asealed casing 54 which encloses a refrigerant compressor and a The com-I pressorand-motor are not shown in the drawvolves and moves the leg 32away from the sliding pin 34. Upon further movement of the ratchet wheel22 in the counterclockwise direction, the cam 52 releases the leg 32which, due to its re siliency, swings back to its normal position andthen, because of its inertia, swings beyond its normal position to drivethe pin 34 to the left. The leg 32 thereafter returns to its normalposition.

A snap-acting switch element 54 is secured at its lower end in thecasing I8 by a bolt 56. This element 54 is best shown in Figs. 3, 5 and6. The

element 54 comprises a switch blade 58 formed of flat spring material.The blade 58 has an inverted Ushaped slot 60 defining an upwardlyextending tongue 62 in the center of the blade 58. A C-shapedcompression spring 54 is interposed between the top of the tongue 62 andthe upper edge of the slot 60. The spring 84 biases the upper portion ofthe blade 58 away from the upper portion of the tongue 62.

Two double-faced contact buttons 66 are affixed, to the upper end of theswitch blade 58. Two sets of contact fingers 88 and '10 are secured inthe upper portion of the casing I8 by bolts 72 and I4 respectively,which bolts also form binding posts for electric conductors. The contactfingers 68 and '10 are so disposed that when the switch blade is in theleft-hand position as viewed in Fig. 3, the two contact fingers it arebridged and when the switch blade 58 is in the righthand position, thetwo contact fingers B3 are bridged. Also, if the tongue 02 is moved tothe left-hand position, as viewed in Fig. 3, the switch blade 58 snapsto the right-hand position and if the tongue 62 is then moved to theright-hand position, the switch blade 58 will snap to the left handposition.

The tongue 62 is positioned adjacent the pin 34 so that when the latteris struck by the leg 32 of the spring element 26 and the tongue 62 is inthe right-hand position, it will be moved to the left-hand positionunder the impact of the pin 34. The bridging of the contact 68 whichresults, causes a cooling unit 16 to be defrosted as will be explainedlater. Since the leg 32returns to its normal position after it strikesthe pin 3 the tongue 02 may be moved to its righthand position withoutfurther movement of the door I4.

When the cooling unit I6 is completely defrosted, the switch blade 58must again be moved to its left-hand position which is the position forthe normal operation of the refrigerating apparatus as will be explainedlater. For this purpose, a second pin I8 is positioned to the leftofthetongue 62. The pin I8 is moved to the right "ings. The compressorwithdraws refrigerant vapor through a suction tube 96 from an evaporatoror cooling unit 16, compresses the vapor and forces it through a tubeI00 into an air-cooled condenser I02. A capillary tube I04 leads therefrigerant liquid from the condenser I02 to the evaporator I6. Athermostatic switch I08 has a thermo-sensitive bulb I08 in contact withthe evaporator I6. A second thermostatic bulb I10 connects with the tube84.

A supply of electric current connects through lead II2 with one of thecontact fingers 68 and one of the contact fingers ID. The other contactfinger I0 connects through lead II4, the thermostatic switch I06 andlead H6 with one terminal of the electric motor in the sealed casing 94.Another lead IIB connects the power supply with the other terminal ofthe electric motor and with one terminal of an electric heater I20. Theother terminal of the heater I20 is connected with the other of thecontact fingers 68 through a lead I22.

Thus, when the switch blade 58 'is in the lefthand position, as viewedin Fig. 6, the contact fingers I0 are bridged and the operation of therefrigerating unit is under the control of a thermostatic switch I06.The heater I20 is deenergized. When the switch blade 58 is in therighthand position, the contact fingers 68 are bridged, the heater I20is energized and the refrigerating unit is rendered inactive.

In some defrosting systems the refrigerating unit operates during thedefrosting period. For such units the two contacts In are not requiredand the lead I I4 is connected directly to lead I I2.

It will be apparent from the above that the invention provides adefrosting control in which the defrosting period may be terminatedwithout further movements of the actuating member I2. It'will be furtherapparent that this invention provides a novel movable dog 36 for aratchet wheel.

While I have shown the invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications without departing from the spiritthereof.

What I claim is:

1. A refrigerator defrosting switch comprising a housing,a switch bladein said housing and biased for snap-acting movement to two positions, aspring element stationarily secured at one end in said housing, a campositioned for rotary movement within said housing and adapted to engagethe free end of said spring element to flex the same and thereafterrelease said spring,

whe1'eu1 Jon said free end swings back to its normal position, themomentum of said free end being such that it continues in its swing tobeyond its normal position, said free end eventually returning to itsnormal position, a member positioned in the path of said free end whenswinging beyond its normal position and adapted to be moved by said freeend, said member when so moved being adapted and arranged to move saidswitch blade from one of its positions if the switch blade is in saidone position to the other of said positions of the switch blade, andmeans responsive to a number of refrigerator operations for rotatingsaid cam.

2. A refrigerator defrosting switch responsive to the opening andclosing of a refrigerator door, said switch comprising a housing, aswitch blade in said housing and biased for snap-acting movement to twopositions, a spring element stationarily secured at one end in saidhousing, a cam positioned for rotary movement within said housing andadapted to flex the free end of said spring element and thereafterrelease it, whereupon said free end swings back to its normal position,the momentum of said free end being such that it continues in its swingto beyond its normal position, said free end eventually coming to restin its normal position, a member positioned in the path of said free endwhen swinging beyond its normal position and adapted to be contacted bysaid free end, said member when so contacted being adapted and arrangedto move said switch blade from one of its positions if the switch bladeis in said one position to the other of said positions of the switchblade, means for rotating said cam in response to the opening andclosing of a refrigerator door, and independent means for returning saidswitch blade to said one position.

3. A refrigerator defrosting switch comprising a housing, a switch bladein said housing and biased for snap-acting movement between a first anda second position, a spring element stationarily secured at one end insaid housing, the opposite end of said spring element being free anddisposed in a region spaced from said switch blade when said sprinelement is unflexed, means for transmitting movement of the free end ofsaid spring element to the switch blade and including a memberpositioned between the free end of said spring element and said switchblade, a cam positioned for rotary movement Within said housing andengageable with the free end of said spring element to flex the same ina direction away from said switch blade and, thereafter, to release saidspring element, the construction and arrangement being such that thebias of the spring element, when released, returns the sprin elementtoward its unflexed position, the inertia of the spring element carryingit beyond said unflexed position before the spring element comes to restin its unflexed position, said movement transmitting means beingactuated by the spring element as the latter passes beyond its unfiexedposition for moving said switch blade from its first to its secondposition, means for actuating said cam, and means for moving said switchblade from its second position to its first position.

GRAHAM S. McCLOY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS McCloy Jan. 11,

